The present invention relates to the production of objects of great length composed of composite fiber materials impregnated with a resin and in particular to the manufacture of bearing beams of great length.
It is known that the manufacture of objects of great length composed of composite materials presents problems which have not been solved at the present time in a completely satisfactory manner, in particular as concerns the polymerization of the resin under heat and pressure owing to the very large size of the required molds and the control of their temperature.
The applicant has developed a method for manufacturing molds for producing objects of great length composed of composite materials, this method being disclosed in French Pat. No. 2,552,012 filed by the applicant. This application discloses a method comprising the following stages: forming a wall of a molding cavity in a plurality of parts and of a cheap material having a high thermal conductivity, applying at least one heating means in direct thermal exchange relation to an external surface of said wall, applying a thermal insulator on top of said heating means, and fixing the various wall parts on rigid mold-supports in uniform pressure transmitting relation to said wall. By means of this method it is now easy and inexpensive to produce objects of large size composed of composite materials.
Thus this method makes it possible to take full advantage of the mechanical properties of the composite materials for easily constructing for example beams and in particular elements or beams having special shapes for particular applications.